Capitol Hill Democrats are mounting an aggressive campaign to denounce and disrupt new Homeland Security deportation raids, as the issue drives a widening wedge between President Obama and his usual allies.

The Department of Homeland Security raids began over the Christmas holiday season and resulted in the initial detention of 121 illegal immigrants, many from Central America.

Anti-illegal immigration groups point out that, despite the angst on Capitol Hill, the targets reflect just a tiny fraction of the overall undocumented population.

But even those initial raids have led to a messy Democratic backlash for the administration – with lawmakers joining every Democratic presidential candidate in opposing them.

“Millions of people are living with fear,” Illinois Democratic Rep. Jan Schakowsky said Tuesday at a Capitol Hill press conference. “This is a serious problem right now that needs to be addressed before more damage is done.” 

The administration has defended the operation by pointing to a sharp increase in Central American families and children arriving at the U.S. southern border and suggesting the influx could lead to a border crisis like the one in the summer of 2014.

Schakowsky and others argue those swept up in the raids are merely refugees seeking relief from gang wars, the drug trade and other violent crime in their native El Salvador, Honduras and Guatemala.  

The congresswoman is one of about 140 congressional Democrats who signed a letter to Obama arguing the raids were made without sufficient outside consultation and asking him to postpone the operation until a better policy can be crafted.

They argue in the letter that ICE agents used “deceptive tactics to gain access to private residence” and that the operation should be suspended until the administration can “assure no mother or child will be sent back to a country where they would back prosecution, torture or death.”

Earlier this week, Democratic presidential front-runner Hillary Clinton joined those calling for an end to the operation.

"I do not think the raids are an appropriate tool to enforce the immigration laws,” she said. “I think they are divisive, they are sowing discord and fear.”

Fellow Democratic candidates Sen. Bernie Sanders of Vermont and former Gov. Martin O'Malley of Maryland already had taken similar stances.

Still, the administration has shown no sign of stopping the operation.

“Only after individuals had exhausted the legal remedies available to them ... was a decision made to remove them," White House Press Secretary Josh Earnest said recently.

On the other side of the immigration debate, critics of the administration’s policies contend the raids are barely making a dent.

The Federation for American Immigration Reform (FAIR) says the raids and related screenings resulted in two arrests on terrorism charges. However, the group, which seeks to limit overall immigration into the country, argues the 121 detained represent a fraction of a percent of the estimated 300,000 illegal immigrants who arrived from Central America in recent years.

“Everything about this action … seems designed to deceive the American public into believing that the administration is trying to stem the surge of Central American illegal migration,” the group said in a statement Tuesday. “The administration pretends to enforce a few immigration laws, and the advocates pretend to be outraged.”

Illinois Democratic Rep. Luis Gutierrez said Democratic opponents, though, fired off their letter after an unproductive meeting with White House Counsel Neil Eggleston.

He said the letter shows the signers have rejected and “discredited” the administration’s “misguided policy of deportation.” 

Democratic aides said Eggleston expressed concerns about the Democrats' approach and the potential impact it could have on the administration's hopes of defending Obama's deportation-relief policies before the Supreme Court.

Administration officials have repeatedly emphasized that they have focused on people who have arrived in this country recently, in line with new deportation priorities announced in late 2014, at the same time Obama announced an expanded deportation relief program, promising to temporarily lift the threat of removal for millions.

They also say the administration has a responsibility to enforce the law and in this case there is a further responsibility not to encourage people to take a very dangerous journey.

New figures Tuesday showed the number of Central American families and unaccompanied children coming from Central America from October to December more than doubled, compared to the same period in 2014.

And the figure could go even higher beginning in February and early spring, when arrivals traditionally increase, potentially eclipsing the levels that produced the 2014 crisis.

While the administration stands by the raids, Secretary of State John Kerry announced Wednesday that the U.S. refugee program would be expanded to help families from El Salvador, Guatemala, and Honduras.

The Associated Press contributed to this report.